Many public and private groups, such as security and safety personnel (e.g., police, fire fighters and ambulance drivers) use various different communication devices operating on various different communication networks. For example, many public service organizations, such as police, fire and emergency management team (EMT), utilize land mobile radios communicating through push-to-talk technologies. Each organization may have its own communication network and/or its own communications channel. However, communications among different endpoints of different networks such as endpoints of different police, fire or other security networks may present a challenge. Collaboration between the different agencies and networks tends to be ad hoc and inefficient. When achieved, it often involves laborious manual intervention. Organizations working towards interoperability solutions include Raytheon JPS Communications, IP Blue, Twisted Pair, M/A-COM, Motorola, EADS, and Cisco Systems.
In addition, many networks of public and private groups, such as security and safety personnel, utilize push-to-talk (PTT) technology to enable communications among members of a particular group. Groups members may communicate using push-to-talk endpoints, such as land mobile radios. Emergency Response Teams (ERTs) utilize PTT devices to facilitate their communication. The convergence of radio PTT and IP networks opens this traditional communication modality to a new wave of innovation. The vast amount of bandwidth enables new functionalities and makes it possible to present multiple channels and virtual talk groups (VTGs) to end users. For example, Cisco System's Interoperability and Collaboration System (IPICS) introduced the PTT Management Center (PMC) client which allows users to participate in up to eight simultaneous PTT sessions. This system will accommodate up to 50 parallel sessions (channels and VTGs). These sessions may involve different public or private agencies, each one with a different communication standard and varied level of security. These two new dimensions (new features and multiple channels) present system designers with a GUI/TUI real-estate challenge of conveying the new readily available information to the end user.
User interfaces of existing PTT devices is typically limited to signaling the status of the floor control. For example, military systems use the following conventions of “beeps” and “bonks:” three beeps after pressing a PTT button means the channel is available and the user may talk; a bonk, steady/broken after pressing the PTT button means the channel is not available; a steady bonk without hearing talking on the radio may mean that the user is out of range or that the talk group or radio is disabled; two beeps after a user releases the PTT button means the radio battery is low. Recording systems play a periodic “beep” to remind conference call participants that their discussions are being recorded. This solution is not practical in a PTT system that involves radios, because air time must be saved for important operation related communication.